The present invention relates to a method for the manufacture of pectinous and sacchariterous preparations, more particularly from fresh fruit or fruit that has been kept fresh and which is stoned or deseeded or cored, fruit flesh, fruit pulps or fruit purees or pastes, such as jam, marmalade or the like. The boiling down of jams, jellies and marmalades from fruit, sugar, pectin and fruit acid is known. Flavor and consistency as well as the conservation and distribution of the fruit essentially determine the quality characteristics of jams, jellies and marmalades. These properties do, however, depend very greatly on the raw materials employed in each case. The characteristic quality of the finished product is imparted by the addition of saccharine substances, pectin and fruit acid. Stone fruit, pomaceaous fruit and berries in a suitable condition are used for the manufacture of jams and marmalades. Refined sugar or white sugar in the form of saccharine solutions which are distinguished by a relatively low viscosity are mainly used for the manufacture of jams; they are temperature-tolerant and do not crystallize out even at a low temperature. Besides sugar, glucose syrup is used for the manufacture of jams and marmalades as well as also uectin and fruit acid, where, especially in the multicomponent systems, the pectin plays the structure-imparting part and is used in the quantity necessary in each case for gelatinization. As fruit acids, inter alia lactic acid, citric acid, tartaric acid and the like are employed which serve to standardize in each case the most favorable pH value, particularly since the most favorable pH value for gel formation lies at 3.0. The standardization of the optimal pH value for the gelatinization process in the manufacture of jams and marmalades is effected precisely by the addition of this fruit acid.
Jams and marmalades are manufactured by the boiling process through which an adequate sugar exchange is achieved between the liquid medium and the fruit in order to prevent an emersion in the finished product during storage. The most widely varying cooking vats have been developed for the industrial production of jams and marmalades, where, two types of inspissation principles are distinguished, viz. boiling down in an open vat under atmospheric pressure and boiling down in a closed vacuum vat at reduced pressure. The manufacture of jams and marmalades in an open vat is still practised in but a few, often small manufacturing establishments. In the first-mentioned process, only the fruit and the mixture of pectin and sugar is first heated to from 80.degree. C. to 90.degree. C. and maintained at this temperature for approximately 5 to 10 minutes. The pectins dissolve. It is the object of the process to dissolve the powdered pectins and to carry out the dissolution process at low temperatures so as to conserve the fruit. However, by way of an alternative, the dissolution of the pectins is also effected by means of a brief ebullition lasting approximately 2 minutes at 100.degree. C. to 102.degree. C. But both steps have disadvantages in that the inevitable and also intended steaming is deleterious to the flavor.
However, in the aforementioned known method, the flavor is exposed in an "unprotected" manner to heating and evaporation. On the other hand, boiling down in the vacuum vat at a reduced pressure has gained ground. In the second boiling process mentioned, to begin with the fruit and the added sugar are heated to 70.degree. C. or 95.degree. C. and intermixed with the aid of appropriate agitators. The preheated mixture of fruit and sugar is then aspirated by the preheater with the aid of a vacuum into the actual cooking vat and concentrated by evaporation in the vacuum while steam is supplied under agitation. The pectin solution is then charged and the concentration by evaporation is continued until the desired final solids are obtained; then, the charging of the acid is carried out, in which case the finished product is filled into receptacles within a temperature range of approximately 75.degree. C. to 85.degree. C. In the vacuum boiling process, however, the boiling down is effected in closed cooking vats under reduced pressure. In this process, the operation is carried out at low boiling temperatures and while use is being made of short boiling times, a significant economy of the method is supposed to result. In this process, too, a preheater is operated which is installed before the actual cooking vat. The technical expenditure which such vacuum boiling facilities entail is relatively substantial. In these processes, all additives are admixed with the fruit in a liquid form.
Since, in the known vacuum methods for the manufacture of jams and marmalades, pectins are added in a swelled or dissolved form and the fruit acid is also added in the form of a solution, all these solutions enter into the total product. In the end the result is a high water content and the high water components have to be evaporated. It is advantageous in the inspissation process carried out in the vacuum cooking vat that the heating be effected at temperatures of approximately 70.degree. C., whereas one has to put up with the drawback that an evaporation of the flavor takes place so that a finished product having a poor flavor content is obtained. That is why boiling installations with flavor recovery facilities are also known in which the volatile flavor components are condensed from the water vapors and added to the boiled material again prior to the preparation being discharged. However, boiling installations of this type are very expensive.
Moreover the quality of the finished product deteriorates it less sugar is present in the product during the boiling down operation itself. Also in vacuum boiling it was realized that the high sugar content is advantageous for conserving the flavor. This is why the boiling down is effected at a low temperature, which, however, again leads to flavor losses.
According to the aforedescribed processes and methods, in particular when jams are produced under vacuum, pectins dissolved in water are used by the industry for the gelatinization of the products. In addition, also on account of economical considerations, crystallized sugar is substituted for glucose syrup and, by this step, further water components are carried into the charged product. Glucose syrup contains only 80% dry matter and 20% water. The undesirable increase of the water content in the charged product--fruit, sugar and glucose syrup--inclusive of the pectin solution can, according to the known methods and for economical reasons, not be avoided. With an additional expenditure of energy, the water content of the pectin solution and of the glucose syrup are then evaporated once more when the jams are manufactured and, in the process, flavors are inevitably lost. It is intended that facilities for flavor recovery and flavoring agent additions will subsequently compensate the flavor losses incurred.